Dr. Wickramasinge reports that a meteorite fell in Sri Lanka on Dec. 29th, 2012. He maintains that fossils of diatoms were found inside a sample of the meteorite he examined. He does not think Earthly contamination is involved, as the diatoms appear to be mineralized in the same manner as the meteorite itself. Interesting news, but far more than merely interesting, If this stands up under independent examination. Link:http://wattsupwiththat.com/2013/01/14/claim-meteorite-discovered-with-signs-of-life-in-it/

Perhaps if they can definitely establish that these organisms are not from Earth, the next question they turn to will be: where did they come from, then? I believe the panspermia concept has life forming in space, and carried about by comets.

Diatoms appeared hundred billions of years after the "genesis".
The oxygenic photosynthesis they use have been invented by Cyanobacteria.
Diatomeen also have an secondary endosymbiosis (with am eucaryotic algae).
They also an N2-fixing endosymbiosis (with Cyanobacteria).

This is the result of a long long evolution on earth.

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I think panspermia is a nice idea. But i think that the originate of life happened on earth.
meteorites may be important for accumulation organic matter.

No particular species of diatoms were identified. It is not clear how we could know at this stage that they are from Earth. It may be possible for similar-appearing unicellular life forms to evolve elsewhere than on Earth.
Parallel evolution is already known to produce similar forms, even among very divergent forms of life. Consider the ichthyosaur, a reptile, sharks, which are fish, and dolphins, mammals. All assumed a notably similar form, independently. We also know from evolutionary history that the eye evolved independently, several times. The eye of the invertebrate octopus is structurally very similar to that of mammals.

yes convergent evolution is common in nature. Same solutions for the same problems.
but its nearly impossible that life on other planets "choose" the same way of evolution.
Diatomeen are well studied. their ecology etc and also their evolution, because they store silic acid (SiO2 · n H2O) in their cell wall. And so you can find them often well preserved.
I know not much about them but when you take a look a the picture you can specify the Order. I looks like O. Pennales because of their bilateral symmetry.
O. Pennales (Eunotiales, Diatomales, Achnanthes or Naviculales), its hard to specify exactly, because you only see one side of this organism.

Bilateral symmetry seems to be one of those features that occur again and again in very many, and very different forms of life. That it should occur in a conceivably extraterrestrial organism does not seem so improbable.
We know that on Earth, very simple organisms can evolve and adapt under a great variety of conditions. No doubt conditions on other planets will be different from those on Earth. Perhaps they will not be *so* different, though, that it will be impossible for simple organisms having many similarities to those on Earth to be produced.
It seems that many features of the diatoms in the Polonnarawa meteorite will have to be carefully examined before we can say with certainty whether this is an Earthly organism, or one that merely has some points of resemblance to same.

I think probably that life got it's start on some planet in our galaxy and upon that planet's destruction the seeds of life got distributed throughout space.

If it evolved out there then why could it not have just evolved here? Seems to me that the idea that life began elsewhere and then came here just adds another layer of complexity to an already complicated and unlikely enough scenario.

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Pure mathematics is, in its way, the poetry of logical ideas.

Bilateral symmetry seems to be one of those features that occur again and again in very many, and very different forms of life.

Yes nearly every high developed has a bilateral Symmetry - the Bilateria.
I just wanted to say that there are two crown-groups of Diatomeens- the Order Centrales engl. Centric(radial) and the Order Pennales engl. Pennate (bilateral)(old system).

.... examined before we can say with certainty whether this is an Earthly organism, or one that merely has some points of resemblance to same.

this discovery need to be checked, true.
But you have to be very careful and critical about this topic.
It states that among competing hypotheses, the one that makes the fewest assumptions should be selected. Occam's razor

Looks like a hunk of basalt, not a meteorite. Before worrying about the diatoms, worry about if the rock came from space.

Dr. Phil Plait who wrote a blog critical of the new discovery said that the object did not look like a meteorite, especially the type of meteorite (carbonaceous chondrite) this is supposed to be. I looked for a few minutes in the Google Image files and found a picture of this type of meteorite that looked a great deal like the one one from Sri Lanka. It is clearly atypical, but is still classed with carbonaceous chondrites. Some good meteor experts will have to look at the specimen itself, not just pictures, before we can really be certain what this object is.

Bilateral symmetry seems to be one of those features that occur again and again in very many, and very different forms of life.

Yes nearly every high developed has a bilateral Symmetry - the Bilateria.
I just wanted to say that there are two crown-groups of Diatomeens- the Order Centrales engl. Centric(radial) and the Order Pennales engl. Pennate (bilateral)(old system).

.... examined before we can say with certainty whether this is an Earthly organism, or one that merely has some points of resemblance to same.

this discovery need to be checked, true.
But you have to be very careful and critical about this topic.
It states that among competing hypotheses, the one that makes the fewest assumptions should be selected. Occam's razor

The two main hypotheses are: 1.) contamination of the object with Earthly algae, and 2.) The presence of non-terrestrial diatoms in the specimen. One could simply argue that since we know that such organisms exist on Earth, and don't know that they exist elsewhere, the first hypothesis is the simpler, thus better. This is correct, but only if it covers all the facts. I am not certain that it does. It is reported that the diatoms appear to be mineralized, and in a manner substantially similar to the body of the host object. Finding this to be the case, Dr. Wickramasinghe, and his associates appear justified in selecting the second hypothesis. . Otherwise they would be required to invent an entirely new mechanism of fossilization that can occur inside a rock, in a matter of days. Their hypothesis will be confirmed or refuted when it is independently determined if the host body is from a recently fallen meteorite, and if the diatoms are truly fossilized.

Bilateral symmetry seems to be one of those features that occur again and again in very many, and very different forms of life.

Yes nearly every high developed has a bilateral Symmetry - the Bilateria.
I just wanted to say that there are two crown-groups of Diatomeens- the Order Centrales engl. Centric(radial) and the Order Pennales engl. Pennate (bilateral)(old system).

.... examined before we can say with certainty whether this is an Earthly organism, or one that merely has some points of resemblance to same.

this discovery need to be checked, true.
But you have to be very careful and critical about this topic.
It states that among competing hypotheses, the one that makes the fewest assumptions should be selected. Occam's razor

The two main hypotheses are: 1.) contamination of the object with Earthly algae, and 2.) The presence of non-terrestrial diatoms in the specimen. One could simply argue that since we know that such organisms exist on Earth, and don't know that they exist elsewhere, the first hypothesis is the simpler, thus better. This is correct, but only if it covers all the facts. I am not certain that it does. It is reported that the diatoms appear to be mineralized, and in a manner substantially similar to the body of the host object. Finding this to be the case, Dr. Wickramasinghe, and his associates appear justified in selecting the second hypothesis. . Otherwise they would be required to invent an entirely new mechanism of fossilization that can occur inside a rock, in a matter of days. Their hypothesis will be confirmed or refuted when it is independently determined if the host body is from a recently fallen meteorite, and if the diatoms are truly fossilized.

IIRC it was reported to be a carbonaceous chondrite which makes it an ET item. The only question left is was it from a recent fall or not?

They seem to have been able to determine if a specimen is a recently fallen one, in other instances of searching for meteorites, after a meteor has been seen falling. I would have thought that this determination would have been made in Sri Lanka, before the specimen was sent to the UK. If not, it could presumably still be done, the meteorite and the site of the fall are apparently less than three weeks old.

Wikipedia is typically quite conservative about controversial scientific claims, rejecting sensationalism. Their article on the Allan Hills meteorite reflects a high level of uncertainty about the presence or absence of fossils microbes therein. This question seems to be far from settled. The article does a good job of explaining why. Link: http://en.wikipedia.org/wiki/Allan_Hills_84001